docs: def derive_depth(self, depth):
          """Derives a new event from this one setting the ``depth`` attribute.
  
          Args:
              depth: (int):
                  The annotations associated with the derived event.
  
          Returns:
              IonEvent: The newly generated event.
          """
          cls = type(self)
          # We use ordinals to avoid thunk materialization.
          return cls(
              self[0],
              self[1],
              self[2],
              self[3],
              self[4],
              depth
          )